Deinking of waste xerographic copy paper

ABSTRACT

A flotation process for the removal of toner from waste xerographic copy paper which comprises adding a thin film of an immiscible organic solvent to an aqueous bath of repulped waste xerographic paper, mildly agitating the stock suspension, and skimming off the accumulated toner contained in the immiscible organic layer.

United, States Patent Green, Jr.

Jan. 18, 1972 {54] DEINKING OF WASTE XEROGRAPHIC FOREIGN PATENTS ORAPPLICATIONS COPY ER 265,488 11/1911 Germany ..l62/5 [72] lnventor:Charles J. Green, Jr., Webster, NY. 502,730 7/1930 Germany [73]Assignee: Xerox Corporation, Rochester, N .Y. lO79858 5/1954 FranceFiled? 1969 Primary Examiner-Frank W. Lutter [21] App]. No.: 821,375Assistant Examiner-Ralph J. Hill Anamey-Dona1d F. Daley, James J.Ralabate and Owen D. Marjama [52] US. Cl ..162/5, 209/162 [51] Int. Cl..D21c 5/02 [58] Field 01 Search ..209/4, 9, 11, 162-165, [57] ABSTRACT2 /172, 171; 162/5 A flotation process for the removal of toner fromwaste xerographic copy paper which comprises adding a thin film of an[56] Relerences cued immiscible organic solvent to an aqueous bath ofrepulped UNITED STATES PATENTS waste xerographic paper, mildly agitatingthe stock suspension, and skimming off the accumulated toner containedin the 1,083,234 12/1913 Werst.. UX immiscible organic layer. 3,069,30712/1962 Boaz ..l62/5 3,432,030 3/1969 Olivier ..209/172 X 9 Claims, 2Drawing Figures REPULPING TRANSFER OF PULP TO AGITATION TANK DlLUTlONMILD AGITATION AT TEMPERATURE OF TO 205 F.

CONTINUAL OF DEVELOPER SKIMMING ADDITION OF IMMISCIBLE ORGANIC SOLVENTSKIMMING OF THE IMMISCIBLE ORGANIC FILM LAYER RECOVERY OF PULPPATENIEUJAHIBIEZZ 3.635 789 SHEET 1 OF 2 REPULPING TRANSFER OF PULP TOAGITATION TANK DILUTION MILD AGITATION AT TEMPERATURE OF 150 TO 205 F.

CONTINUAL SKIMMING OF DEVELOPER ADDITION OF IMMISCIBLE ORGANIC SOLVENTSKIMMING OF THE IMMISCIBLE ORGANIC FILM LAYER RECOVERY OF PULP I IINVENTOR. FIG, CHARLES J. GREEN JR.

ATTORNEY PAIENIEDJNWQYZ 3.635.789

SHEET 2 OF 2 REPULPING DILUTION TRANSFER OF PULP TO FIRST MILD AGITATIONAGITATION. TANK SKIMMING OF THE DEVELOPER PLACING A THIN FILM OF ANIMMISCIBLE ORGANIC SOLVENT ON SAID SUSPENSION TRANSFER OFPULP SUSPENSIONTO SECOND AGITATION TANK MILD AGITATION SKIMMING .OF THE ACCUMULATEDDEVELOPER I o NIC AYER RECOVERY OF THE PULP N RGA FIG. 2 v

DEINKING OF WASTE XEROGRAPI-IIC COPY PAPER BACKGROUND OF THE INVENTIONThis invention relates in general to a process of deinking paper and inparticular to a process of removing electroscopic marking material ortoner from copy paper.

Conventional methodsof deinking and reclaiming waste paper which havebeen used in the pastwith some success involve the cooking of thewaste-stock in various deinking chemicals'Such methods were reasonablysatisfactory and adequate a number of years ago when there was no needto deink and reclaim newsprint, and the balance of the waste paper didnot contain ground wood. Such papers were printed with standard inksthat werereadily removed or saponified with chemicals at elevatedtemperatures.

In recent years, however, methods of deinking involving cooking and theuse of chemicals have become increasingly unsatisfactory for a number ofreasons. Ink formulations have become more and more complex and involveincreasingly use of a wide variety of synthetic resins and plasticizerswith each ink company having its own special formulations. Alsoincreasing amounts of synthetic resins and plasticizers are being 'usedin a wide variety of sizings and coatings. Furthermore,

multicolored printing and multicolored advertisements have becomeincreasingly important in recent years and these involve a wide varietyof new ink formulations many of which incorporate new pigments, dyes andtoners which are adversely affected by various deinking chemicals. Theseformer methods of deinking and reclaiming waste paper by the use ofchemicals and cooking procedures are therefore not adapted or adequatefor removing these new types of inksand coating formulations. Due totheir high content of thermoplastic resins, the softening action of theheat chemicals alone make the separation from the fibers very difficult.Furthermore, the action of the heat and chemicals tends to irreversiblyset and more firmly bond to the fibers some of the present-day pigmentsand to fix dyes and toners to the fibers through staining.

For these and other reasons it will be seen that the deinking inreclaiming processes for waste paper which were in use in the past areno longer satisfactory or adequate for many current needs.

While the deinking-and reclaiming processes of the prior art have becomeless and less effective because of the technological advance of thepaper-making art the need for a satisfactory deinking and reclaimingprocess has become increasingly important due to the greatly expandedutilization of paper and the consequent depletion of timber reservesthroughout the world.

-With the progressive depletion of natural resources becoming an everincreasing problem, the need for developing useful and efficientpaper-reclaiming processes becomes of critical importance.

A particular area in which conventional deinking techniques areunsatisfactory in reclaiming waste paper is in the area ofelectrophotography which is better known as xcrography. In the art ofxerography an electrostatic latent image is formed by uniformly charginga photoconductive insulating surface of a xerographic plate followed byexposing the charged surface to a pattern of light. The latent imageformed by this technique is then developed with electroscopic powder,also known as toner, to forma powdered image which is then transferredto a sheet of normal bond paper. This powder image now contained on thepaper is then fused into the paper to form a permanent reproduction ofan original image. Reuseable photoconductive insulators such as vitreousselenium and alloys of selenium can be used over and over again toproduce thousands of copies. In another variation of the xerographicprocess, a photoconductive paper is used.

This paper is coated with a layer of photoconductive insulating materialwhich is usually dispersed in a film-forming resin. The coated paper isimaged in the same manner described above for reusable xerography. Inusing the paper, however, the developed powder image is fixed directlyto the paper containing the photoconductive insulating layer and notransfer is necessary.

One technique now ingeneral use for developing xerographic images iscascade development. This technique is based on the phenomena oftriboelectrification whereby upon bringing two similar materials intocontact each material becomes electrically charged to a polarityopposite to that of the other. Thus when the fine powdered toner ismixed with the relatively coarse beaded carrier, the toner particlesbecome charged triboelectrically and cling to the surfaces of thecarrier beads. Development of the electrostatic image is accomplished byfalling or cascading the two component developer over the surface of thexerographic plate. As the beads, covered with toner, roll over theimage, the electrostatic forces of the image overcome the carrier-tonerbond, and toner particles are deposited'on the image areas. An exampleof a toner composition for this type of application consists of 25percent polyvinyl-butyral, 70 percent of a rosinmodifiedphenol-formaldehyde and 5 percent carbon black which is disclosed inU.S. Pat. No. 2,753,308 to Landrigan. Various other formulations such asthose disclosed in U.S. Pat. Nos. 2,638,416, to Walkup et al., and2,735,785 to Grieg et al., can be used.

Another means of xerographic development is liquid electrophoreticdevelopment which has particular utility when photoconductive paper isxerographically processed. Developers may be prepared by dispersingfinely ground pigments such as zinc oxide, phthalocyanine blue ornigrosene in an insulating hydrocarbon liquid such as toluene, carbontetrachloride, or petroleum fractions. The pigment particles acquireelectrical charges during dispersion and remain suspended in a liquid.When a photoconductive paper containing electrostatic image of thepolarity opposite to that of the dispersed particles is immersed in theliquid. the pigment particles migrate and become fixed on the latentimage.

Since ever increasing amounts of xerographic copy paper are being usedeach year effective processes for reclaiming the waste xerographic paperare very much needed. However, the effectiveness of any deinking processmust take into account the fact that in the xerographic processdevelopment compositions consist of complicated organic compositions andthe resulting image is fixed on the printed copy. With regard to tonerdevelopment, as heretofore indicated the toner is usually made offuseable resins or resin blends in which a pigment such as carbon blackhas been-dispersed. The resins are selected to provide the propertriboelectric relationship with the carrier beads and to provide amelting point within the proper range for heat fixing, or sufiicientsolubility for solvent vapor fixing. With regard to liquid development,the pigments migrate by the phenomena of electrophoresis" to the paperand are fixed to its surface. In essence, the action of heat, chemicals,or electrophoresis in the xerographic processes purposely print fixeddevelopment composition to the cellulosic fibers of the paper therebyalmost irreversibly staining said paper.

SUMMARY OF THE INVENTION In accordance with the present inventiona novelprocess for deinking waste xerographic paper has been discovered andsuccessfully reduced to practice. The instant process relates to apractical flotation technique for removal of toner from wastexerographic paper. The equipmentnecessary for carrying out the presentprocess may be conventional laboratory apparatus or commercial machinerypresently available in paper mills. Therefore, very little additionalcapitalization would be required for new equipment in usingthe processof the instant invention. Furthermore, the present invention makes useof common organic solvents as chemical additives which give it obviouseconomic advantages in considering its use.

It is therefore an object of this invention to provide a process fordeinking waste xerographic copy paper that is both economical andrelatively easy to perform.

It is another object of this invention to provide a process for deinkingwaste xerographic copy paper that produces a reclaimed pulp which may beadapted to the manufacture of conventional types of paper.

These and other objects are obtained in accordance with the presentinvention, wherein there is provided a method for deinking, i.e. removalof toner composition from waste xerographic copy paper. The instantprocess involves the application of the flotation process to wastexerographic paper; that is, the present deinking process relates to therelative capacity of toner particles to float in an aqueous solution. Inparticular, the present deinking process comprises adding a thin film ofan immiscible organic solvent to an aqueous batch of repulped wastexerographic paper, and after mild agitation for a period of about to 30minutes, removing the accumulated toner and said immiscible organiclayer. While many variations of this deinking process may be used, aswill be hereinafter disclosed, the essential elements necessary to carrysaid process out are the following:

a. the use of an immiscible organic solvent film layer in the agitationstep, or if there is more than one agitation, then in the finalagitation step;

b. the adjustment of the agitation such that no vortexing or excessivemixing takes place, thereby insuring against the redistribution of thefloated toner;

c. the skimming of the toner must take place as quickly as possible inorder to avoid its saturation and subsequent redistribution in the pulpsuspension.

BRIEF DESCRIPTION OF DRAWINGS In order that the invention may be clearlyunderstood, reference will now be made to the accompanying drawings inwhich two embodiments of the invention are illustrated.

FIG. 1 is a flow diagram illustrating one embodiment of the instantinvention.

FIG. 2 is a flow diagram which illustrates one embodiment of acommercial application of the present invention.

In carrying out one specific embodiment of the present deinking andreclaiming process reference is made to FIG. 1 where the xerographicwaste paper is first pulped by any conventional technique in a suitablefiberizing apparatus such as a hollander beater, jordan or a pulper suchas the one sold by the Black-Clawson Co. under the trademarkHydrapulper. The pulping, or repulping, consists in reducing the drywaste xerographic copy paper to fibrous form, with enough water added toaid processing and freeing the material of excess fiber bundles or otheruncommunicated material.

The repulped stock is then transferred to an agitation tank and dilutedwith an amount of water sufficient to suspend the fibersi While thedegree of dilution is not critical as long as the fibers are suspendedin the aqueous slurry, a concentration of from about 0.5 to 2 percent byweight pulp is preferred. At this concentration the individual fibersare not only suspended in the slurry, but can move freely without anydanger of agglomeration. The repulped stock is then mildly agitated at atemperature of from about 150 F. to 205 F. The agitation must be mild tothe extent that any surfacing toner is not physically redistributedthroughout the slurry. By way of illustration, when a stirrer agitatoris used the mixing must take place without vortexing.

The toner composition which has surfaced during the mild agitation iscontinually skimmed off while the bath is being agitated. While theskimming should continue as long as toner appears at the surface, itshould generally be continued over limited periods of between 15 to 45minutes in order to insure against saturation and redistribution of thetoner particles.

A sufficient amount of immiscible organic solvent is then added to forma thin film layer over the stock suspension and mild agitation isresumed. While the agitation should continue for a period to effectivelyrelease the remaining toner from the fibers, generally the agitationshould be carried out for a period of between l5 and minutes in order toavoid saturation and redistribution. Upon completion of the mildagitation, the immiscible organic layer with the accumulated residualtoner is skimmed off and the cleaned pulp reclaimed in any conventionalmanner.

It should be noted that while the above process has been described interms of distinct steps, for purposes of illustration variations in saidsteps without detracting from the spirit of the present invention areapparent to one skilled in the art. By way of example, the whole processcould be carried out in the repulper or the method performed with onlyone agitation.

As described above the present invention, although simple inapplication, can easily be scaled up to mill size operations. A largescale commercial process can be carried out by means of the followingsteps which are illustrated in the flow diagram of FIG. 2:

a. repulping the waste xerographic copy paper in a commercial device,

b. transferring the stock suspension to a first agitation tank,

c. mildly agitating the soft stock suspension,

(1. skimming the toner which surfaces in the agitation tank,

e. transferring the stock suspension to its second agitation tank andplacing a thin film or organic liquid on the stock suspension,

f. mildly agitating the stock suspension in a second agitator, and

g. skimming off the accumulated toner contained in the organic layer andreclaiming the cleaned paper pulp.

The flow diagram shown in FIG. 2 is exemplary of a typical large-scaleprocess incorporating the concepts of the present invention. Refen'ingto FIG. 2, the waste paper is first introduced into a pulper orfiberizer. This apparatus may be either a batch-type beater or acontinuous-type beater, a socalled Hydrapulper, or any other suitablecommercial device for converting the waste paper into a pulp which canbe pumped through a large-scale system. The pulping can be perfonned attemperatures ranging from room temperatures up to 212 F. Preferably, thepulper is one that operates continuously and therefore in as short aninterval of time as possible.

After the repulping treatment, the pulp is then pumped or transferred toa first agitation tank and there diluted and mildly agitated. Asheretofore mentioned, optimum dilution would be to between about 0.5 and2 percent pulp and the temperature at which the agitation should takeplace should be from about F to 205 F. Also the agitation must becarried out mildly to avoid physical redistribution of the floatedparticles.

Upon initiation of the mild agitation, toner will begin surfacing. Atthis point skimming of the toner should begin and should continue for aperiod of from about 15 to 45 minutes, depending on the amount of tonerin the slurry. Generally in a large-scale process where a large amountof pulp is agitated, a large portion of developer will rise to the surf::e. The skimming operation should be carried out quickly, that is within15 to 45 minutes, so as to avoid saturation redistribution.

At the point in the agitation step where no additional toner appears tosurface, the paper stock is then pumped or transferred to a secondagitation tank. A thin film of an immiscible organic liquid is thenfon'ned on the surface of the slurry. The slurry is then mildlyagitated, without vortexing, to avoid redistribution, and the remainingtoner accumulated in the immiscible organic liquid overlayer. The mildagitation is continued for a period of 15 to 30 minutes. After theagitation has been completed the immiscible organic overlayer with theaccumulated toner is removed and the pulp reclaimed or thickened by anyconventional process.

It should be understood that any number of variations and modificationsof the described process would occur to one who is skilled in the art.However, it is essential for the process described above that bothagitations be mild, that is, in the case of a stirrer-type agitator thatthey take place without vortexing, such that there will be noredistribution of the surfaced toner. It is further essential that theflotation, or skimming,

after each agitation takes place as quickly as possible to avoid thewetting of the toner which will result in a redistribution in the pulpsuspension. In addition, while the first agitation and skimming takeplace without the immiscible organic layer this in no way detracts fromits importance in the process. The use of the immiscible organic solventin the first agitation is optional in that a large quantity of wastexerographic paper is repulped in a large-scale process and thereforeduring a first agitation'a large quantity of loose toner will float tothe surface without the aid of the organic solvent.

For the purposes of the instant invention any organic liquid which formsa distinct physical layer when added to an aqueous solution can be used.However, optimum results are obtained when the organic solvent has asolubility of less than grams per 100 cubic centimeters of water at C.Any suitable organic solvent may be used. Typical solvents includebenzene, toluene, cyclohexanone, xylene, tetrachloroethylene, and methylisobutyl ketone.

In carrying the present invention, it is necessary to have a completeaqueous suspension of the repulped xerographic waste paper so that theremoval of all the toner particles is possible. This may be accomplishedby various mechanical or chemical means known to one skilled in the artof paper technology. By way of example, dispersing aids such as sodiumhexametaphosphate, manufactured by the Calgon Corporation and sold underthe trademark Calgon, alkyl phenoxypolyethoxy ethanol, manufactured bythe Rohm and Haas Company and sold under: the trademark Triton X100 ortetrasodium pyrophosphate can be used in dispersing the pulp.

Although the theory or mechanism for the success of the deinking processof this invention is not completely understood, it is believed that theimmiscible organic solvent functions to soften the toner composition byway of partial disolution and to provide a surface to which the toneradheres and agglomerates. Hence, when a fixed toner composition,

which has been loosened from the fibers of the paper, comes into contactwith the organic solvent, the toner particles become agglomeratedthereby forming larger particles which are subsequently skimmed 01?.

According to the present deinking process, various grades of paper suchas newsprint, bond, and book paper can be made from the wastexerographic paper which has been reclaimed in accordance with thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following examples furtherspecifically define the present invention with respect to a method ofdeinking waste xerographic copy paper. The percentages in thedisclosure, examples, and claims are by weight unless otherwiseindicated. The examples below are intended to illustrate variouspreferred embodiments of the process of deinking waste xerographic copypaper.

EXAMPLE I A 5-pound batch of waste paper is introduced into a batchtypebeater supplied with cold water at a temperature of 70 F. In additionabout 1 percent by weight, based on the fiber content, of Calgon isadded in order to aid dispersion. The batch is then subjected to pulpingfor a period of 20 minutes. At the end of the beating operation thestock is pumped to an agitation tank. The stock is then diluted to apulp concentration of 1 percent. The resulting slurry is thenmechanically stirred to efiect a mild agitation, that is, withoutvortexing. Almost immediately the solid particles of toner appear at thesurface of the slurry and are skimmed off every few minutes. Theskimming takes place for a period of minutes at which time a sample ofthe pulp is taken and handsheet No. l is made. At this point enoughcyclohexanone is added to the slurry to produce a thin-film organiclayer over the surface of the batch. Mild agitation was resumed for aperiod of 30 minutes at which time the cyclohexanone layer withaccumulated developer is removed. A sample of the pulp is taken andhandsheet No. 2 is made.

Of the two samples handsheet No. 2 is superior in quality in that thereare no specks of toner present. Handsheet No. l is of poor qualityhaving a great many toner specks throughout its surface. It can be seenfrom the results of example I that the organic liquid overlayer is veryeffective in removing the residual toner which remained on handsheet no.1.

The following experiment is performed to indicate the importance of mildagitation to the present process.

EXAMPLE II A 5-pound batch of waste xerographic paper is subjected to apulping and agitation process according to the method of example I.After the addition of the cyclohexanone film layer and several minutesof mild agitation, the stirring rate is increased to a rate whichresults in vortexing of the slurry. As a result, the accumulated tonerwas redistributed throughout the slurry. The agitation was then sloweddown and flotation of the toner particles in the cyclohexanone layer wasresumed. Thereafter a sample of the pulp was taken and a handsheetprepared. The handsheet exhibited dispersed toner particles throughoutits surface and was greatly inferior to handsheet No. 2 of example I,which clearly indicates the detrimental effects of vortexing.

While the invention has been described in terms of a preferredembodiment, it is to be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the true spirit and scope of theinvention. In addition, many modifications may be made to adapt aparticular situation or material to the teaching of the inventionwithout departing from its essential teachings.

What is claimed is:

l. The method of deinking waste xerographic copy paper to reclaim thefiber content as clean pulp suitable for reuse, comprising the steps of:

a. repulping the waste xerographic copy paper,

b. transferring the repulped stock to a first agitation tank anddiluting the entire mass,

c. mildly agitating said stock solution, without vortexing, at

a temperature less than boiling,

d. skimming the toner which has risen to the surface of the firstagitation tank,

e. transferring the stock solution to a second agitator tank and placinga thin film of an immiscible organic liquid on the surface of saidsolution for the purposes of accumulating residual toner,

f. again mildly agitating said stock solution, without vortexing, and

g. skimming off the accumulated toner in the organic layer andreclaiming the cleaned pulp.

2. The method of claim 1 wherein the repulping takes place in a pulper.

3. The method of claim 1 wherein the mild agitation takes place for atime period of from about 15 to 45 minutes.

4. The method of claim 1 wherein the organic liquid is cyclohexanone.

5. The method of deinking waste xerographic copy paper to reclaim thefiber content as clean pulp suitable for reuse in papennaking,comprising the steps of:

a. repulping the waste xerographic copy paper,

b. transferring the repulped stock to a first agitation tank anddiluting to about 1 percent pulp,

c. mildly agitating said stock solution, without vortexing, at

a temperature less than about 212 F.,

d. skimming the toner which has risen to the surface of said firstagitation tank,

e. transferring the stock solution to a second agitator tank and forminga thin film of an immiscible organic liquid on the surface of saidsolution for the purposes of accumulating residual toner,

f. again mildly agitating said stock solution without vortexing, at atemperature below about 212 F., and

g. skimming oft the accumulated toner in the organic layer andreclaiming the cleaned pulp.

6. The method of claim wherein the organic layer is cyclohexanone.

7. The method of deinking waste xerographic copy paper so as to reclaimthe fiber content as clean pulp suitable for reuse in paper makingcomprising the steps of: 5 b

as to reclaim the fiber content as clean pulp suitable for reuse inpaper making comprising the steps of:

a. repulping the waste xerographic copy paper in a pulper at about roomtemperature up to about 212 F., transferring the stock to a firstagitation tank and diluting a. repulping the waste xerographic copypaper in a pulper at a temperature up to about 212 F.,

b. transferring the stock to a first agitation tank and diluting theentire mass to about 1 percent pulp,

mildly agitating said stock solution, without vortexing, at

a temperature of about 200 F.,

. skimming off the toner which has risen to the surface of said firstagitation tank for a period of about 30 minutes,

e. transferring the stock suspension to a second agitator tank andplacing a thin film of an immiscible organic liquid on the surface ofsaid solution for the purposes of accumulating residual toner,

again mildly agitating said stock suspension, without vortexing, for aperiod of about to 30 minutes and at a temperature of about 200 F., and

g. skimming off the accumulated toner in the organic layer andreclaiming the cleaned pulp.

8. The method of deinking waste xerographic copy paper so the entiremass to about 1 percent pulp,

c. mildly agitating said stock solution, without vortexing, at

atemperature of about 200 F.,

. skimming off the toner which has risen to the surface of said firstagitation tank for a period of about 30 minutes,

e. transferring the stock suspension to a second agitator tank andplacing a thin film of an immiscible organic liquid on the surface ofsaid solution for the purposes of accumulating residual toner,

. again mildly agitating said stock suspension, without vortexing, for aperiod of about 15 to 30 minutes and at a temperature of about 200 F.,and

g. skimming off the accumulated toner in the organic layer andreclaiming the cleaned pulp.

9. The method of claim 8 wherein the organic liquid is cyclohexanone.

2. The method of claim 1 wherein the repulping takes place in a pulper.3. The method of claim 1 wherein the mild agitation takes place for atime period of from about 15 to 45 minutes.
 4. The method of claim 1wherein the organic liquid is cyclohexanone.
 5. The method of deinkingwaste xerographic copy paper to reclaim the fiber content as clean pulpsuitable for reuse in papermaking, comprising the steps of: a. repulpingthe waste xerographic copy paper, b. transferring the repulped stock toa first agitation tank and diluting to about 1 percent pulp, c. mildlyagitating said stock solution, without vortexing, at a temperature lessthan about 212* F., d. skimming the toner which has risen to the surfaceof said first agitation tank, e. transferring the stock solution to asecond agitator tank and forming a thin film of an immiscible organicliquid on the surface of said solution for the purposes of accumulatingresidual toner, f. again mildly agitating said stock solution withoutvortexing, at a temperature below about 212* F., and g. skimming off theaccumulated toner in the organic layer and reclaiming the cleaned pulp.6. The method of claim 5 wherein the organic layer is cyclohexanone. 7.The method of deinking waste xerographic copy paper so as to reclaim thefiber content as clean pulp suitable for reuse in paper makingcomprising the steps of: a. repulping the waste xerographic copy paperin a pulper at a temperature up to about 212* F., b. transferring thestock to a first agitation tank and diluting the entire mass to about 1percent pulp, c. mildly agitating said stock solution, withoutvortexing, at a temperature of about 200* F., d. skimming off the tonerwhich has risen to the surface of said first agitation tank for a periodof about 30 minutes, e. transferring the stock suspension to a secondagitator tank and placing a thin film of an immiscible organic liquid onthe surface of said solution for the purposes of accumulating residualtoner, f. again mildly agitating said stock suspension, withoutvortexing, for a period of about 15 to 30 minutes and at a temperatureof about 200* F., and g. skimming off the accumulated toner in theorganic layer and reclaiming the cleaned pulp.
 8. The method of deinkingwaste xerographic copy paper so as to reclaim the fiber content as cleanpulp suitable for reuse in paper making comprising the steps of: a.repulping the waste xerographic copy paper in a pulper at about roomtemperature up to about 212* F., b. transferring the stock to a firstagitation tank and diluting the entire mass to about 1 percent pulp, c.mildly agitating said stock solution, without vortexing, at atemperature of about 200* F., d. skimming off the toner which has risento the surface of said first agitation tank for a period of about 30minutes, e. transferring the stock suspension to a second agitator tankand placing a thin film of an immiscible organic liquid on the surfaceof said solution for the purposes of accumulating residual toner, f.again mildly agitating said stock suspension, without vortexing, for aperiod of about 15 to 30 minutes and at a temperature of about 200* F.,and g. skimming off the accumulated toner in the organic layer andreclaiming the cleaned pulp.
 9. The method of claim 8 wherein theorganic liquid is cyclohexanone.